Control method and apparatus



Dec. 23, 1941. R. N. CONWELL ETAL CONTROL METHOD AND APPARATUS Original Filed Dec. 17, 1935 5 Sheets-Sheet l fizz/1v M CdIV/VELL 6255?? 5. 5/309;

1941- R. N.'CONWELL ET AL 66,

CONTROL METHOD AND APPARATUS Original Filed Dec. 1'7, l955 3 Sheets-Sheet 2 Fall/Al A! C awn/a1. 618597 ififiw/rfs 1941- R. N. CONWELL ET AL CONTROL METHOD AND APPARATUS s Sheets-Sheet 3 Original Filed Dec. 17, 1935 \WWQ 1 3 MP@ ID Tu QNm Patented Dec. 23, 1941 CONTROL METHOD AND APPARATUS Rollin N. Conwell, Bloomfield, and Albert S. Brookes, Newark, N. J.

Continuation of application Serial No. 54,958,

December 17, 1935. This application May 16, 1938, Serial No. 208,300

11 Claims.

Our invention relates to systems of remote control of loads on polyphase alternating-current power distribution systems. This application is a. true continuation of our co-pending application Serial No. 54,958, filed December 17, 1935.

It is particularly applicable for remote control of loads such as multiple street lights and storage hot water heaters. Our system will furnish remote control for many types of electrical apparatus such as the multiple street lights and storage hot water heaters above mentioned, as well as other types of load which are generally connected to secondary mains fed from the usual distribution transformer. Among the advantages of the system is that it furnishes a low cost and positive control for electrical apparatus which it is desired to operate from some remote point.

Where a multiple system of street lighting is used, such as in the suburban districts of cities, it almost invariably happens that there is not sufficient load to warrant the running of feeders exclusively for street lighting. Consequently these lights are connected to the service or house lighting feeders. House lighting service must be continuous. Therefore, the problem of turning the street lights on and oil immediately presents itself. Switches that are operated by clock mechanism are unreliable for this work, as they are in the case of storage hot water heaters or other types of heating load.

For the remote control of loads on polyphase alternating-current lines there have been heretofore suggested the use of 60-cycle control current and relays, or carrier-current operated relays using say 480- or 720-cycle current. The 60- cycle alternating-current control system is subject to false operation by stray alternating currents under conditions not at all unusual in power distribution systems. For example, induced voltages from the power line to the control wire due to fault conditions or unbalanced loads would cause 60-cycle alternating current to flow in the control wire and hence cause false operation of the relays. In the carrier-current system relatively complex and expensive control units are required, and the starting of heavy equipment or fault conditions may give rise to harmonics which cause false operation of the relays.

An object of our invention is to permit remote control of electrical apparatus to be accomplished over a control wire such as a pilot wire ,or the neutral of a four-wire system.

Another object of our invention is to provide a system which is positive in operation, economcal to construct and maintain and which will furnish a system of positive control of remotely located apparatus.

In accordance with the present invention direct-current actuated relays and direct-current control is employed for the remote control of loads on a polyphase alternating-current distribution system. Means are provided for sufficiently limiting or substantially preventing alternating current from flowing through the relays and thereby affecting the operation of the relays. The use of direct-current relays and direct-current control, in combination with means for preventing alternating current from flowing through the relays, renders the present system free from false operation by alternating currents which may be induced in the control wire or directly impressed thereon by unbalanced or fault conditions on the power line.

With these and other objects in View, which may be incident to our improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising our invention may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

In order to make our invention more clearly understood, We have shown in the accompanying drawings means for carrying the same into practical effect without limiting the improvements in their useful applications to the particular constructions, which, for the purpose of explanation have been made the subject of illustration.

In the drawings:

Figure 1 is a diagrammatic view of our system as applied to a three-phase four-wire distribution main employing a polarized relay as the controller;

Figure 2 is a diagrammatic view of our system, showing a three-phase three-wire distribution main, and a pilot wire system of control using a polarized relay as the controller;

Figure 3 is a top plan view of a polarized relay which we may use;

Figure 4 is a View taken along the line 44 of Figure 3, looking in the direction of the arrows;

Figure 5 is a view taken along the line 5-5 of Figure 3, looking in the direction of the arrows;

Figure 6 is a diagrammatic view of our system employing a three-phase four-wire distribution main and a sequence relay;

Figure 7 is a view in side elevation of a sequence relay which We may employ.

There is a source of direct current supply which we have indicated by the numeral Qthatis connected through a reversing "switch it to the neutral Wire 6 and ground of the distribution circuit. In operation, it is to be understood that the grounding switch must be opened to loolt 43 to an insulating block 44. block44is adapted to carry a contact element 45having aconnecting bar 46 having contacts 41 In Figures 3, 4 and 5 we have shown details of the polarized relay which we may employ. In general we have given a description of the polarized relay, but it is believed to be useful to give somewhat more of a detailed description of certain of the parts. The switch, which we have generally indicated by the numeral '28, comprises support *mem'bersAil pivoted asindicated at 41. On the top of the'supportmembers 461 is a connecting bar 42 which is attached by means of the The insulating thereon. Contacts 4'! are adapted to contact adjacent contacts 48 mounted on conductor brackets 49 which-areconnected to the support permit the system of remotecontrol towork A.

resistor 8' of sufficiently high're'sistance to avoid an excessive drain on the direct current supply is connected across the terminals of the switch 8.

At the locality wherethe remote control must be exercised, we have connected to neutral wire 6a lead H which passes through a choke coil I2 and thence through actuatingcoils l3-andl4 of a polarized relay or controller. Each of the actuating coils i3 and I4 is provided with short circuiting turns l3 and i4: respectively. We may connect across the actuating coils a condenser l5. line l6 which connects to a line H.

Connecting the wire 5 to the wire ll is a -line I8 containing the primary. E9 of a distribution transformer. A secondary 26 ofthe'transformer is connected to conductors 2!, 22 and 230i the secondary feeder main. The conductor 22 is connected to ground through a lead-24, as shown.-

The actuating coils l4 and I3 are adapted one to repel and the other to attract a permanent magnet 25 which is pivoted at 26;, and :whichjsv adapted through a yoke 2'! to open'or closega switch 28. The switch 28 is connected to the lead ll which connects to'the line 22.-

The switch is also connected to a lead 29 which is connected to a lead 32 of multiple street lights 3|. Lead of the multiple street lights is connected through a wire 33 to wire 23 of the. secondary feeder main. s

In operation, the grounding switch 8 is open and the reversing switch Ill. is operated'tofsend direct current in either desired direction-along the neutral wire 6 of the distribution circuit;

Current fiows through neutral conductor 6,- through lead l I, through choke I2, through actuating coils l3 and M of the polarized. relay, through lead ll to wire 22, to wire 24 and thence to ground, whence the circuit is cornpleted through a ground 34 connected'to lead 1. Depending upon which way the reversing switch 10 is thrown, the direct current'will operate on the polarized relay to open or close the switch 28,

turning on or turning off the lights 3! of the multiple street light circuit. v

The choke coil l2 limits the flow of alternating current through the polarized relay. The short circuited turns l3 and M on the actuating. coils l3 and M, respectively, of the polarized; relay render the effect of any alternating current which may get throughnegligible. Furthenfthe condenser which may optionally bencon'nected across the coils l3 and I4 further renders negligible the effect of the alternatingcurrent'onthe polarized relay. Where we use the term fpolarized relay we of course intend to referto polarized controllers in general andlnot'be limited to the narrow meaning of the-term relay.

From the actuating coils there, is a-.

the leads IIand ZS'to the polarized relay.

Each of the brackets 49 is insulated from the other bracket. With the position of the parts shownHas-in Figure 5, an electrical circuit will becompleted through each bracket 49, contacts 43. contacts 4Tand connecting bar 46. The yoke 2'iis adapted to pivot the supports 40 about'the pivots 4! to either, make orbreak the; circuit; The bolt 43 has attachedtoit a tensions-pring 52 which is attached as indicated at 53 to the base of asupport .bracket'54 ;uponwhich the.

permanent magnet 25 is =pivoted at 26 The construction is such that-thetension-ofthe spring 52 is in a direction which-isoff center, from the pivot point4l of the switch in eitherthe on or the off position {of the-switch.-. The spring 5 2 therefore tends V to hold the sw itch "either in theoni or off .position- After: the permanentmagnet'Z ii'lias b'eeniactuated to set theswitch, the switch will remain inthe-position set until the permanent Y magnet 7' 25 L is actuated in r the other 7 direction to change" the switch setting.

Referring to Figurel we haveshown a system as applied to a three-phase three wire distributioncircuit rather than 'a three-phase four-wire distribution circuit. TWith thetln-ee-wire distribution circuit, weernployinstead of the neutral wirei a pilot wiretmwhich connects to reversing. switch.lfl'fand through a lead at to the ground 34. In this systemtheprimary l9 of'the distribution transformer is connected to wires 4 andSTth'rough leads 62 'and 63. There is ahead 64 to the pilot Wire GlYwhiCh corresponds to lead H of the system shownin Figure 1. Theremainder of theconnections are the same;

In this form of systemthe operationof the polarized relay or controller for turning o'n or off the multiple. street lights, storage hot waterheaters, or other desired apparatus, is. effected through the pilot wire by the reversing switch H];

In Figs. l' and 2 the neutral=wire vor-pilotwire,

respectively, is connectedlto ground- IMat the control station, so that in either. casethe control wire is at a relatively lowpotential with respect to ground. Hence the relay and associated equipment at 'thedistant station are required-towithstand only relatively low voltage and, are therefore relatively inexpensive. l'n a ccordan'ce withusual practice, the neutral fi'Yor pilot wire 60-- will be strung on the same poles or carried in the same underground duct as the poWerwires, 3,4, 5, so that the controlwire is in proximity with the, powerlinefor a substantialportion: of the distance from the control station to the distant station.

The choke coil 12, short circuit turnsJ3 l4?,.

and condenser L5 if Linea offer a, rnuch greater impedance to alternating. currentthan to direct Y current and therefore serve to sufficiently limit or substantially prevent the flow of alternating current through the relay, thereby preventing alternating current induced in the control wire or otherwise impressed thereon from aifecting operation of the relay and proper control of the load.

Instead of employing a polarized relay or controller, we may employ a sequence relay or a sequence controller. We have shown in Figure 6 a sequence relay or sequence controller which we have shown connected to a three-phase fourwire distribution system, in which the neutral wire is employed to effect the operation of the sequence relay at the distant point. It is obvious that a pilot wire could be used as was shown in the system illustrated in Figure 2, in case the three-phase distribution system should be a three-wire instead of a four-Wire system.

In general, a pilot wire instead of a neutral wire may be used where the neutral is unavailable, or in cases where it is unsuitable for use. The unsuitability may arise from the presence of grounds at points other than at the station.

In the system illustrated in Figure 6, there is a lead I connected to a neutral wire 6 of the four-wire distribution circuit. The lead I00 is adapted to be connected through a switch IM to a source of direct current I02. The switch IOI also connects the lead I03 to ground I04. There is illustrated the usual neutral grounding switch 8 which must be opened to permit of the remote control.

' Connected to neutral wire 6 is a lead I05 in which is connected a choke coil I06 which, through lead IN, is connected to an actuating coil I08 of a sequence relay. The actuating coil I08 may have a condenser I09 connected across its ends, as illustrated in dotted lines. The actuating coil I08 is connected to a lead IIO which is connected to the wire 22 that is connected to the secondary 20 of the local transformer. The primary I9 of the distribution transformer is connected through a lead III to the wire 5 and to the lead I05.

There is provided a short circuited turn I08 for the actuating coil I08. Pivoted above the actuating coil I08 is an armature member II2 which is pivoted at I I3. At the end of the armature member is pivoted at II4 a pawl II5 which is adapted to engage with ratchet teeth H6. The ratchet teeth I I 6 are on a ratchet wheel I IT. The ratchet Wheel III is attached to a disc II9 having flat cam surfaces I20 and hollowed out cam surfaces I2I.

Adapted to bear against cam surfaces of the disc H9 is a spring member I22 which carries at its end a contact I23. The contact I 23 is adapted to make or break contact with a contact I24 mounted on a support I25.

The spring element I22 and support I25 are connected respectively to leads I I0 and alead I26, which latter connects with the wire 32 of the multiple street lights 3|.

Pawl H5 is held against the ratchet teeth II6 by means of a spring I21 (see Fig. '7). The armature I I2 is held in the up position by means of a spring I28 which is attached to an extension I29 of the armature at one end and at its other end to a bracket I30 upon which the armature is pivotally mounted at H3 and upon which the actuating coil I 08 is also mounted.

A spring I 3I is adapted to contact the cam faces of the disc II9 to furnish a frictional holding member for the disc to prevent accidental displacement of the disc from its adjusted posii I I I I li"- II The operation of the sequence relay is very simple. The limiting position of the armature H2 is controlled by an adjusting nut I32 which limits the upper position, and adjusting nut I33 which limits its lower position. When the armature I I2 is moved in its down position, the pawl II5 engages a ratchet tooth IIS and moves the ratchet II'I clockwise, looking at the parts in the position shown in Figure 7. Upon cessation of flow of current in the actuating coil I08, spring I28 pulls the armature II2 into its up position. Springs I3-I or I22 hold the disc H9 in the position which it has taken after being moved by the armature II 2. It is to be noted that when the spring I3I is riding on a. flat surface I20 of the disc II9, the spring I22 has its bentout portion I35 lying within one of the depressions I2I of the disc IIO. When the portion I35 of the spring is lying on one of the faces I20, the spring I3I is lying within one of the depressions I2I of the disc H9; thus the disc II 9 will be held in its adjusted position.

When the portion I35 of the spring I22 lies on the surface I20, contact is made between contacts I23 and I 24. This causes current to flow through lead III! through the contacts I23 and I24 to lead I25 through the multiple street lights and back through a lead I40 to Wire 23, thus causing the lights to go on. On the next move of the sequence relay under an impulse sent out by closing the switch IOI, the circuit above described is broken by parting of the contacts I23 and I24.

From the above description it Will be apparent that by closing the switch IOI the direct current from the direct current source I02 will in sequence open and close, and open and close the circuit which controls the street lights 3 I.

Throughout the specification, where We have used the term polarized relay, we also refer to polarized controller, and where we have used the term sequence relay we also refer to a sequence controller. A polarized relay is a relay which will close its contacts when direct current is caused to flow through it in one direction and open its contacts when current is caused to flow through it in the reverse direction. The selecting mechanism may be through the use of permanent magnets or through the use of rectifying elements in series or parallel with the relay coils.

By sequence relay is meant a relay which closes the contacts on the first impulse or series of impulses and opens the contacts on some following impulse or series of impulses. The various aforesaid impulses may be similar or they may differ in polarity, magnitude or duration, or any combination of these characteristics.

While we have shown and described the preferred embodiment of our invention, we wish it to be understood that we do not confine ourselves to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

We claim:

1. In a polyphase alternating current power distribution system, a system for the remote control of loads from a distant control station comprising a control wire extending from the control station to a distant station at which control is to be effected, a load, a switch for connecting said load ito. said alternating current" power distribui tion system at said distant station, a direct current actuated relay' at'zsai'dx distant stationaconnected in circuit withsaidv'control wire andadapted to operate said: switchgmeans :atlsaid control stationifor impressingldirect current on said controlwire tmtherebyrcontrolzthe operation of 'saidxrelay at thezs distant station, and means 'for. substantially: preventing alternating: current, due tov voltagesxinducedinuthe= control wire or abnormal conditions on thepower system.

from flowing through said re'layandrthereby affecting the operation thereof.

2. In a polyphase alternating current"powerdistributionsystemz. a system for the remotecontrol of' loads .from" a distant control l station com-. prising acontrol wire extendinglfromzthe control station to a distant z'station at which controlis-to be 'efiected, a load; a :switch for'rconnectingsaid load to'said alternating current power distribution system a at :said distant station, a. direct current actuated sequence relay at said distant station connected. in. circuit :withsaid cotnrol wire I and adapted to operate said switch, means at said control station .for. impressing direct current on said controLwire.tottherebycontrol the operation' of said. relay at thedistant' station; and

means for. substantiallywpreventing. alternating.v

current,v due to voltages induced: in the control wire or abnormal. conditions on therpower system from flowing through'said'frelay. and thereby"af-.-

fecting. the :operation thereof.

3. In a polyphase alternating current power.

distribution system; aesystem for. the remotecontrol of loads froma :distant control station'comprising a control wir'eextendingrrom the control station to a distant station at whichcontrol is to be effected, a load, .a switch for'connecting said.

load to said alternating.currentipower distribution system atsaid distant station, a polarized relay at said distant station connected in; circuit with said control -wire and adapted-to open'and close said'switch, -means:at' said," control station for impressing directcurrent onsaidcontrol wire alternatively in either "direction to thereby operate said. polarized relay, and-means for substantially-preventing alternating current, due to voltages induced' in the control "wire or" abnormal conditions on the power system; from flowing through said relay'and:therebyafiecting the operation thereof.

4. In an alternating current power distributing system in which poweris transmitted from a control station to a distant distribution station. by a polyphase transmission line having a neu tral wire, a system for the remote control of loads comprising a load, a: switch for connecting said loadtosaidalternating current-power distribution system at said-distant distribution system; forlthe remote control of said loadsfrom a distant 1 control station on f the high voltage transmissionxline comprising-a control wireextending from said control station onithe high-- voltage transmission-line to a' distant station on the low-voltage distributing-line, aload, a switch for connecting said load to the low-voltage distributing line at said J distant station, a' direct current actuated: 1 relay at said distant station connected in.circuit with said control wire and adaptedxto operatecsaidswitch, means at said controlstation for impressing direct current-on said control wireto .thereby control'the operation of saidrrelay at the distant station, and meansifor sufficiently limiting the flow of alternating current; due to voltages induced in the control-wire or abnormal conditions on the power system, 'irom flowing through said relay and thereby affecting the operation thereof.

6. Inazpolyphase alternating current power distribution system in which .power' is transmitted 'atrairelatively high voltage'and is transformed to a: relatively lowivoltage atv a distributing station for supplyingaloadstherefrom, .a

1 system ,for the remote. control :of said loads. from adistant control station on. the high-voltage transmission .line comprising a, control wireextending'fromsaid control station on the highvoltage transmission linetoa distantstation on ;thelow-voltage distributing line, saidcontrol wire having a relatively'low.potentia1.'with respect'to ground, a :load, a switch for connecting said load to the low-voltage distributing line-lat said distant station, a polarized'relay' at said zdistant station connected in circuit -with'saidcontrol-"wire-and adapted to open and close said switch, means atsa-id control station in impressing direct current on said control wirealternatively in either direction to thereby operate said. polarized relay, 2 and means for: suffrciently limiting the flow of alternating current, duetovoltages induced in-the controlwire or abnormal conditions on-ithei power system, from flowing through saidrelay and thereby afiecting the operation thereof.

7. In an alternating current power distribution system in'whichpower is transmitted at a-rela tivelyhigh voltage-from a control station to a distant distributing station by'a, polyphase transmission linefhaving a neutral wire .and'is-transformed'atsaid distributing station to arelatively low voltage for supplying a load, a system for theremote control' of; said load. comprisinga switch -for'connecting said load to the low-voltage alternating current line from saidxdistant distributing station, a direct current actuated relay at I said distant "distributing station con nected-in circuit with theineutral wire of said high" voltage transmission: line and; adapted to operate said switch, meansiat said controlstation for-impressing direct current on. said neutral wire to thereby operate saidi relay, and means for suificiently limiting theifiow of alternating current, due to unbalanced conditions in the polyphase system, through said relay to prevent said alternating current from affecting the actuation thereof.

8. In a polyphase alternating current. power distribution system in which power is transmittedata relatively high voltage and is transformed to a relatively "low voltageat'a distributing station forisupplying loads therefrom, a.

system for the remote control'of said loads from a distant control station on" the-highevoltage. transmissionilineacomprising aspilotwirez extende 1 ing from said control station on the high-voltage transmission line to a distant station on the lowvoltage distributing line, said pilot wire being grounded at said control station, a load, a switch for connecting said load to the low-voltage distributing line at said distant station, a polarized relay at said distant station adapted to open and close said switch, said polarized relay being connected in circuit between said pilot wire and ground, means at said control station for impressing direct current on said pilot wire alternatively in either direction to thereby control the operation of said polarized relay at the distant station, and means for substantially preventing alternating current, due to voltages induced in the pilot wire or abnormal conditions on the power system from flowing through said relay and thereby afiecting the operation thereof.

9. In a polyphase alternating current power distribution system of relatively high voltage, a system for the remote control of loads from a control station on the high-voltag line comprising a control wire extending from the control station to a distant station at which control is to be eiTected, said control wire having a relatively low potential with respect to ground, a load, a switch for connecting said load to said alternating current power distribution system at said distant station, a direct-current-actuated relay at said distant station connected in circuit with said control wire and adapted to operate said switch, means at said control station for impressing direct current on said control wire to thereby control the operation of said relay at the distant station, and means rendering the impedance of the actuating circuit of said relay sufliciently greater for alternating current than for direct current to prevent alternating currents in the control wire due to induced voltages or abnormal conditions from affecting proper control of the load.

10. In a polyphase alternating current power distribution system, a system for the remote control of loads from a distant control station comprising a control wire extending from the control station to a distant station at which control is to be efiected, said control wire being in proximity with the power distribution line for at least a substantial portion of the distance from the control station to the distant station, a load, a switch for connecting said load to said alternating current power distribution system at said distant station, a direct current actuated relay at said distant station connected in circuit with said control wire and adapted to operate said switch, means at said control station for impressing direct current on said control wire to thereby control the operation of said relay at the distant station, and means for substantially preventing alternating current, due to voltages induced in the control wire or abnormal conditions on the power system, from flowing through said relay and thereby affecting the operation thereof.

11. In a polyphase alternating current power distribution system of relatively high voltage, a system for the remote control of loads from a control station on the high-voltage line comprising a control wire extending from the control station to a distant station at which control is to be effected, said control wire being in proximity with the power distribution line for at least a substantial portion of the distance from the control station to the distant station and having a relatively low potential with respect to ground, a load, a switch for connecting said load to said alternating current power distribution system at said distant station, a direct-current-actuated relay at said distant station connected in circuit with said control wire and adapted to operate said switch, means at said control station for impressing direct current on said control wire to thereby control the operation of said relay at the distant station, and means rendering the impedance of the actuating circuit of said relay sufficiently greater for alternating current than for direct current to prevent alternating currents in the control wire due to induced voltages or abnormal conditions from airecting proper control of the load.

ROLLIN N. CONWELL. ALBERT S. BROOKES. 

